The present invention relates to an improvement in sealed lead-acid batteries.
Sealed lead-acid batteries in which oxygen gas generated at the positive electrode during charging of the battery is absorbed by the negative electrode are available in two types, a retainer type and a gel type. In batteries of a retainer type, a separator (glass separator) in mat form which is made of fine glass fibers is inserted between the positive and negative plates so as to isolate the two electrodes and to retain the sulfuric acid electrolyte necessary to perform discharging. These types of batteries have recently come to be used with portable equipment and as backup power supplies for computers. However, the disadvantages of batteries of a retainer type are the high cost of the glass separator and their inability to retain an adequate amount of electrolyte, which renders it unavoidable that the discharge capacity is limited by the quantity of electrolyte when low-rate discharge is effected. Because of these shortcomings, the commercial use of sealed lead-acid batteries of a retainer type has been considerably limited.
Gel type sealed lead-acid batteries are less expensive than batteries of a retainer type, but their performance is inferior to the latter.